Furnace grate



' 6, 1932'. A. w. BENNIS FURNACE GRATE Filed Oct. 8, 1923 2 Sheets-Sheet 2 Patented Dec. 6, 1932 PATENT OFFICE ALFRED WILLIAM BENNIS, OF BOLTON, ENGLAND FURNACE GRATE Application filed October 8, 1928, Serial No. 311,168, and in Great Britain November 23, 1927.

The present invention relates to chain grate and the like furnaces and more particularly of the type in which grate bars are mounted on carrier bars extending transversely across the mate.

It has been found that a proportion of the fuel material or ash supported on the grate falls down or riddles between the grate bars into the spaces below the upper run or fuel 0 supporting portion of the grate.

It has also been found that in chain grate 'stokers or furnaces of this type and also of the compartment type of chain grate that as much as 1% of burnable fuel passes through the grate before it is heated sufficiently to become sticky and particularly is this the case where very line fuel is used, a loss of such fuel naturally taking place at or near the front end of the grate. This fuel which has dropped through the grate-remains on the lower portions of the carrier bars until these pass round the wheels or drums at the rear end of the grate whereupon it is dumped with the clinker and other waste which has fallen through the grate at the intermediate port-ion and becomes lost for the purpose of combustion.

The present invention comprises means for collecting the fallen unburnt fuel independently of the fallen ashes or like waste.

According to the present invention, one or more receptacles are mounted to the carrier and are adapted to be displaced at any time relative to the carrier bar during the travel of this from the front to the rear of the grate.

Preferably the receptacle is in the form of an extension of the base of the carrier bar and is pivoted to such base, in which case this extension takes the place of the normal longitudinal horizontal portion and is adapted to b-eangularly displaced about the carrier bar proper.

It will thus be seen that by angularly displacing the receptacle of the carrier bar at that point on the grate when any further material passage of line fuel ceases and prior to the passage through the grate of a material portion of ashes or waste products such fine unburnt fuel can be collected independently of the ashes or waste products and can then be passed back to the grate. In this way the efliciency of the stoker is not impaired by the possible loss of a portion of the unburnt fuel.

The invent-ion is more particularly described with reference to the accompanying drawings in which Figure 1 is a diagrammatic fragmentary longitudinal sectional View of the upper run of a travelling grate, showing the principle of working.

Figure 2 is a longitudinal elevation with portions in section showing the complete run of a suitable form of grate constructed according to the invention with a slightly modified chute arrangement.

Fig. 3 is a transverse section through the grate, showing the connections of the receptacle operating shafts.

Fig. 4 is a detail view, corresponding to a portion of Fig. 1, but showing another modification of construction.

In the drawings the grate comprises a plup rality of grate bars 1 which are mounted on transverse carrier bars 2 extending across the grate, these carrier bars being supported on driving chainsll moving along rails or supports extending longitudinally of the grate, and spaced apart across the width ofthe grate, the number of such chains and rails being dependent on the width of the grate.

' In the embodiment of the invention as il- I lustrated in the drawings receptacles 3 are provided of arcuate trough-like form, these receptacles being pivotally mounted to the base 4 of each carrier bar by means of the hinges 5 and extending between adjacent rails on which the carrier bars are mounted or between the end rails and the sides of the grate.

It will be obvious however that it is not essential that the receptacles 3 are formed as shown in the drawings. For example, they may be formed merely as horizontal exten- If sions of the base portion 4 of the carrier bar pivoted to this at 5 or further, they may be V-shaped in cross section as in 3a in Fig. 4.

Runner rails 6 are provided for the support of the receptacles 3, these runner rails the rails.

Each section comprises its own carrier bars, drlven by its chains, and its own receptacles, the combined transverse dimensions of the chains 11 and receptacles 3 being equal to the len th of the carrier bar. Accordln l each section of receptacles is provided with its own runner rails 6 independently of the other sections. The runner rails 6 may be interrupted at any number of points along their length.

For example, as shown in Figure l of "the drawings, they may be interrupted at three points along their complete run, the first point some little distance away from the front of the grate so that unburnt fuel which has passed down beneath the adjacent grate bars and been retained by the receptacles 3 is deposited into a chute 7 by the angular displacement of the receptacles 3 due to their lack of support at the interrupted portion of The runner rails 6 are therefore preferably first interrupted immediately beneath the grate at that portion where fine unburnt fuel is no longer likely to be situated on the upper run of the grate. The second gap or interruption of the runner rails 6 preferably takes place at the termination of. that portion of the upper run of the grate in which comparatively large ashes are likely to pass between adjacent grate bars, such comparatively large ashes beingdeposited into the chute 8 whilst the runner rails may have a third gap or interruption substantially ad- 'jacent the rear of the grate so that fine ash which has passed between adjacent grate bars in the path of travel of these froma position above the chute 8 to'the end of the grate may I a be deposited into the chute 9.

It will thus be seen that collection of the material. passing through the grate bars is effected at definite predetermined points along the pathof travel of the grate bars.

The receptacles'3, as will be seen from the drawings, are held in their closed position to allow of accumulation of the material passing between adjacent grate bars until they reach the gaps in the runner rails, whereupon they tend to assume a vertical position by reason of their own weight in order to deposit the material to the various chutes. When the carrier bars 2 pass over the gaps between the runner rails the receptacles 3 are again angularlydisplaced about their pivots 5 to assume their normal position fer the collection of waste products passing through the grate bars.

It will be seen from Figure 1 of the draw ings that the runner rails at their gaps are curved as at 10 in order to provide for gradual angular displacement of the receptacles 3. 1 V

In the construction according to Figure 2 which shows a complete run of the grate, the fine unburnt fuel is collected in the chute 7 whilst the remainder of the fuel in the form of ash which passes through grate bars during their travel along the upper run of the grate from a position above the chute 7 to the position at the end of the grate, is collected in the chute 12 substantially adjacent the endof the upper run of'the grate. In

this figure it will be noticed that adjacent runner rails 6 overlap at 13.

If desired, a water trough may be placed at the base of these chutes as at 80; into which waste products are dumped.

1 If desired, the chute 7 for the collection of fine unburnt fuel may be formed between a pair of air chambers A. B. situated near the front of the grate, this chute being provided at its base with any known means for collecting the unburnt fuel at either side of the grate and for-transferring such unburnt fuel back to the hopper or fuel bunkers for subse quent supply to the grate, by means of a con veyer diagrammatically shown at 7 a in Fig. 2.

I declare that what I claim is 1. A furnace grate compr sing a dr ving chain, grate bars supported on said chain, a plurality of collecting receptacles supported onsaid chain and located beneath the bars to receive material whichpasses through said bars, a plurality of chutes located along the lengtlrof the grate for receiving material discharged from said collecting receptacles whereby such materials are segregated ac cording tot-he port on of such travel at which they pass through said bars, and means to prevent a discharge of said collecting receptacles between said chutes.

2. A furnacechain grate comprising a dI-lVlIlg chain, grate bars supported on sand.

chain, a plurality of collecting receptacles pivotally supported on said chain and located beneath the grate bars to receive materials which pass through said grate bars, and means extending along the length of the grate for supporting the receptacles in collecting position, said means being interrupted to provide gaps at a plurality of points along the path traveled by'sa-id grate bars while supporting fuel for combustion, whereby said receptacles are individually supported be tween said gaps and are permitted to drop and discharge by gravity at said gaps so that the materials passing through the grate bars aresegregated according to the portion of such travel of the grate bars at which they i passthrough said bars.

3. A furnace chain grate comprising a driving chain, grate bars supported on said chain, a plurality of independent receptacles pivot-ally supported on said chain to move therewith and located beneath said grate bars, a runner rail extending along the length of said grate beneath the path of said receptacles whereby said rails may engage said receptacles individually to hold them in collecting position in which they receive materials passing through the grate bars above them, said runner rails comprising sections spaced apart longitudinally at a plurality of points along the length of the grate so that the receptacles may individually drop by gravity at such points for discharging the material collected therein, and chutes located beneath the gaps between the longitudinally adjacent runner rail sections to receive the materials discharged from the receptacles, whereby such materials are segregated according to the portion of such travel of the grates at which they pass through said bars.

4. A furnace chain grate comprising drive chains, carrier bars supported on said chains, grate bars supported on said carrier bars, a plurality of receptacles individually pivoted to said carrier bars to travel with said bars and chains and located beneath the grate bars, runner rails located beneath said receptacles and extending in the direction oi travel of said grate whereby said rails may engage said receptacles individually to hold them in collecting position to receive materials passing through the grate bars above them, said runner rails comprising sections spaced apart longitudinally at a plurality of points to provide gaps larger than the size of the receptacles in the direction of their travel so that the receptacles may individually be rocked by gravity at the gaps for dis charging the materials therein, and chutes located beneath the gaps between longitudinally adjacent runner rail sections to collect the materials discharged from the receptacles, whereby such materials are segregated according to the portion of such travel of the grate bars at which they pass through said bars.

In witness whereof, I have hereunto signed my name this 20 day of September, 1928.

ALFRED XVILLIAM BENNIS. 

